The present invention relates to a process for the preparation of polyol fatty acid esters, in which fatty acid esters are reacted with a polyol having at least 4 hydroxyl groups, or an ester thereof, in the presence of fatty acid soap and a catalyst.
In a further aspect the invention relates to the use of the polyol fatty acid esters thus prepared in foodstuffs, pharmaceutical compositions, detergents and coating compositions.
In this specification by "polyol, having at least 4 hydroxyl groups" is meant any aliphatic or aromatic compound comprising at least 4 hydroxyl groups, and by "an ester thereof" is meant any partial fatty acid esters of such a polyol, which are intermediates in the conversion of polyol to higher polyol fatty acid esters.
The aforementioned process is known in the art. It is described in U.S. Pat. No. 3,963,699 (G. P. Rizzi & H. M. Taylor), U.S. Pat. No. 4,517,360 (R. A. Volpenhein), U.S. Pat. No. 4,518,772 (R. A. Volpenhein) and J. Am. Oil Chem. Soc. 55 (1978), 398-401 (G. P. Rizzi & H. M. Taylor), U.S. Pat. No. 3,792,041 (Yamagishi et al.).
A drawback of the conventional processes is that the conversion rate of polyol to polyol fatty acid ester is relatively low. In particular, when carrying out these processes batchwise, it takes a rather long time before a desired conversion is reached, during which time the reaction vessel will not be available for a subsequent batch.